He is being held in connection with a package left on a Jubilee line train which sparked a major terror alert.

Witnesses described the dramatic moment armed cops swooped just after midday.

Emi Koizumi told the Standard: "We saw loads of police, including armed (police) and also plain clothed (officers) with their faces covered.

“The plain clothed police ran off down the street towards Highbury Corner right as we walked up.

RELATED STORIES

TERROR ARREST

Cops arrest man, 19, on terror charges over suspicious item left at O2 station

Terror scare

British Airways flight from London to US evacuated after 'bomb threat'...as Greenwich student reveals her fear

TUBE SCARE

Stratford station evacuated 24 hours after counter-terror police carry out controlled explosion at North Greenwich

'WE COULD HAVE DIED LIKE RATS'

Terror as tube passengers are stuck in a lift for 90 minutes on London Underground

“No one would tell us what was going on under the railway bridge.”

Another witness said: "He was struggling not to get arrested, for like a good five minutes.

"They were shouting 'armed police, don't struggle'.

"Everything happened so quick."

He described the man as white, in his early twenties and wearing a hoodie.

A Metropolitan Police spokesman said: "Officers are keeping an open mind regarding any possible motive. They are not looking for anyone else in relation to this investigation at this stage."

Today the Met said high visibility patrols are also being carried out by British Transport Police (BTP) officers.

It is hoped the measure will reassure the travelling public.

Passengers were urged to remain vigilant and report anything concerning to the authorities.

Will Geddes, founder of private security firm International Corporate Protection, described the Tube network as "pretty safe" and said the suspect "couldn't have picked a more modern Tube line" in the Jubilee line.

He told the Press Association: "There's very extensive CCTV and security measures which will have expedited the process of identifying the suspect.

"If they used an Oyster card it's another identifier that links the suspect to the package.

"In terms of the response by the authorities it couldn't have been more efficient and effective, which provides reassurance to the general public in how capable and rehearsed our authorities and emergency services are in responding to these kind of events."

Following the discovery of the suspect device, Manuel Cortes, leader of the Transport Salaried Staffs Association, called for the Tube network to be shut down "until we are given assurances that it's made as safe as possible".

But North Greenwich station was reopened on Thursday night and the Underground returned to normal operation.

Mr Geddes said: "It's always going to be a difficult call.

"If they felt that the threat could not be isolated and controlled then yes they probably would have closed the entire line down.

"However, we know that the Tube is a lifeline for London and the many thousands of people who travel on it every single day."

We pay for your stories! Do you have a story for The Sun Online news team? Email us attips@the-sun.co.ukor call 0207 782 4368.